| Abstract
| - Noble-metal-free active catalysts for the oxygen reduction reaction (ORR) in an acidic environment wereprepared from the pyrolysis of acetonitrile at 900 °C over alumina and metal-doped alumina. This workincludes analyses of the nitrogen-doped carbon preparation process, characterization of the carbon materialsformed, and activity testing for the ORR. The nitrogen-containing carbon nanostructures that formed duringthe pyrolysis of acetonitrile could be purified by washing the product with hydrofluoric acid. A wide rangeof techniques were used to characterize the solid carbon products of the acetonitrile decomposition. Whilethe samples have many similar physical properties, X-ray photoelectron spectroscopy and transmission electronmicroscopy showed evidence that differences in the nanostructure and surface functional groups of the samplesare likely to account for observed differences in oxygen reduction activity. The most active catalysts wereprepared over alumina impregnated with up to 2 wt % Fe, although the catalysts that were prepared byacetonitrile pyrolysis over alumina with no metal doping still had significant activity. In comparison to a 20wt % platinum on Vulcan carbon catalyst, the most active samples only have an additional 100 mVoverpotential. The selectivity of the catalysts for complete oxygen reduction to water followed a trend similarto activity. The best selectivity to water versus peroxide obtained was 99%, or equivalently, an n of 3.98 (i.e.,3.98 electrons transferred out of a maximum of 4 electrons per mole of oxygen that is reduced), as determinedby rotating ring-disk electrode testing.
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